In December 1988 the ancient arena of Nîmes is for the first time covered with temporary roofing – a lens-shaped pneumatic form commissioned for winter-season use. Meant to be assembled and dismantled twice a year, the lightweight structure keeps careful distance between the ancient walls and the new roofing. The discreet solution, characterized by its very low section, from the exterior hardly renders visible the fact that within the old Roman walls something has changed. Inside the arena, the shape of the new roof does not limit the natural upward lift of the ancient elliptical theatre seating. The pneumatic construction is an integrated contemporary solution, technically compatible with the monument.
Catalyst for a mixed city
The structure impressively symbolizes the idea of a European city, honoring histories while providing new opportunities for a contemporary and future public via integrative design and innovative technologies. The amphitheatre of Nîmes demonstrates a principle of entanglement with the urban fabric – simultaneously concentrated and connected – thus embodying a contemporary model of the mixed city.
Running counter to an assimilative language, the autonomous and independent element within the ancient arena’s cavea refrains from interacting, keeping a significant distance from the structure; the result: a lenticular pneumatic form, floating freely above the elliptical area of the arena, the lower convex lens enclosing not like a lid, but somehow retaining a lightness, open to the sky.
The roof consists of two translucent polyester tarpaulins of 4,200 m² that create an air cushion 13 m high.
Both membranes covering the arena are made of a PVC-coated polyester fabric; the lower membrane rests on a network of cables to reduce its interior curvature.
The structure itself consists of an elliptical steel compression ring with hinged cushioned membranes. This highly flexible compression ring is bowed and stabilized simultaneously. The self-stabilizing steel ring, similar to a wheel hub, rests on 30 supporting metallic columns
The roof and the steps are connected by a transparent and adjustable cimbia composed of polycarbonate sheets mounted on aluminium supports, allowing the public inside to fully appreciate the monument. The cimbia was carefully researched down to the last detail as regards to shape, curvature, assembly and storage. The hollow box girders have a wingspan of 6.35 meters, with a height of 150 mm and a width of 450 mm. The principle was based on slat prototypes developed by Merlo, a Turin company specializing in sun protection systems.
Cyclical use and economic demands require the weight and dimensions of all components to be intensely calibrated, taking into consideration potential expansion and shifting of materials as a result of climate and regular handling.
All components are designed and factory-manufactured to the nearest millimeter before being assembled on site, without the possibility of an on-site adjustment.
These requirements help further our approach in seeing architecture not purely as an explicitly formal activity, but as a system of complex interactions between dynamic states and singular parts.
Despite the roof’s "weightlessness", a powerful shape persists, completely lacking in nostalgic elements, an air cushion confronting the monolithic stone. This architecture is not a frontal attack against established patterns and ruins but develops out of 'practical knowledge' which makes a critical contribution towards the enduring life of this historical monument. A crowded urban vista is met by the weightlessness of an interior intervention enabling the ancient facility a modern day use.
The new roof guarantees maximum illumination for the auditorium, offers both technical and acoustic insulation for the complex, and provides air circulation via the rotating sheets of the inclined cimbia façade.
A winter flight over Nîmes reveals a glowing lens exposed and hovering above the amphitheatre. However, while the stone skeleton of the arena rests hulking and immobile, the NAC shelter is temporary and reversible. Besides the mounting apparatus, in the summer months no element of the 6,000 m2 construction remains. Contrary to its first impression this massive structure is not final and immutable, but carries within itself the principle of its cyclical addition and removal.
Installation of a mobile and temporary roofing to create a winter show space in the antique arena (1st century AD). The inflatable membrane lens (91m x 62m) is held in a compression ring on 30 metallic columns. The periphery is closed by a system of transparent and revolving coverslips.
Client: City of Nîmes
Status: since December 1989 yearly erection
Location: Nîmes, Gard, France Arènes antiques, Place de la République
Cost: 6.50 Mio€ (value 1989)
Surface: 8,000 m², Inflatable Lense measures: 91m x 62m
Architects: LABFAC, Finn Geipel, Nicolas Michelin; Structural Engineers: Werner Sobek; Schlaich, Bergermann and Partner, Stuttgart; Acoustic Engineers: Roger Lamoral, Cannes; Civil Engineers: Guy Bonardi, Paris; Construction Firm: Baudin Châteauneuf, Orléans; Façade Engineers: Merlo, Turin; Engineers for the membrane: Stromeyer Ingenieurbau, Konstanz; Sound: Christian Heil, Gonnesse; Execution: Baudin Châteauneuf, Orléans; Electric Engineer: Bet Bleuse; Photography: George Fessy